An Introduction to Flat Roof Waterproofing

You should evaluate how effective your flat roof waterproofing is. Your home is at risk from leaks and severe dampness if your roof isn’t well waterproofed.

flat roof waterproofing

If you have flat roofing anywhere on your home, it’s very important you make room in your budget for some decent flat roof waterproofing. As a previous article mentioned, flat roofs aren’t durable in the slightest compared to other roofing. Their poor resistance to severe weather means they’re not an ideal choice for countries with a damp climate, like the UK.

If your flat roof isn’t waterproofed effectively, your home’s energy efficiency will be highly reduced and could become a source of dampness, condensation, mould and coldness. When the pooling of water on flat roofing is almost inevitable at some point during its lifespan, flat roof waterproofing should be compulsory if you don’t want water to leak into your home.

How much does flat roof waterproofing cost?

This depends on the material you use. The most common materials used for flat roofing are felt, fibreglass and EPDM (a type of rubber). Felt is the cheapest option, at about £9 per square metre. Fibreglass is very slightly more expensive at £11 per square metre and EPDM is the most expensive option at around £18 per square metre.

If you are hiring a roofer, you’ll obviously have to take into account labour costs on top of the cost for material. Flat roof waterproofing can be done by yourself on smaller roofs, but if you have a larger requirement you should call in a professional, who can bring along a team if necessary.

What’s the best material for flat roof waterproofing?

With felt being the cheapest option also comes the fact that it’s not the best for waterproofing. For anyone on a tight budget this might be the preferred option, but it’s not as advisable to use it on a home as it is on a garden shed, where insulation and energy efficiency aren’t big priorities. Felt has the shortest lifespan and tends to allow water to pool more than other materials. It will need repairing or replacing more often as well.

Fibreglass is only a tiny bit more expensive but is much more effective. Fibreglass protects very well against water damage. It can however, become very costly if you’re trying to cover a large area, and you should hire a professional to fit it because it’s an irritant. EPDM might be a fair bit more expensive, but it provides a rubber membrane which gives great protection from the elements and won’t need to be replaced anywhere near as often as felt.

You could also go for a sheet metal roof, made from lead, zinc, stainless steel or copper. These are much more durable than any other flat roof waterproofing material, and this is reflected in the price. Lead roofing costs around £50 per square metre, and zinc, stainless steel and copper can cost closer to the £100 per square metre mark. These will also need to be fitted by a specialist contractor. You’ll need to consider whether the initial expense is worth a roof which is more durable, more energy efficient and much greener.

Image: Lynne Hand

post your comment




One of the most effective ways to encourage wildlife into your garden is by introducing a pond. This guide will show you how to build a pond which your local wildlife will thank you for!

how to build a pond

Here's just a few useful and fun ways you can use the shells of pistachios and other nuts instead of throwing them away

pistachio shells

Find out how to keep your sugar intake low and avoid health problems such as joint inflammation and heart disease


Patagonia's unique approach to revealing information on their manufacturing process is something all aspiring green businesses could take a tip from.